Locomotive



Dec. 23, 1930. M. K. INGOLDBY 1,786,304

LOCOMOTIVE Filed July 8, 1926 6 Sheets-Sheet 1 INVENTOR' ATTORNEY-5 Dec. 23, 1930. 'M. K. INGOLDBY 7 1,786,304

LOCOMOTIVE Filed July 8, 1925 6 Sheets-Sheet 2 Dec. 23, 1930. M. K. ,INGOLDBY LOCOMOTIVE File y 8, 1926 6 Sheets-Sheet 3 Dec. 23, 1930. M. K. INGOLDBY LOCOMOTIVE Filed July 8 1926 4 6 Sheets-Sheet 4 Dec. 23, 1930. M. K. INGOLDBY 1,786,304

Lobbuo'rlva Filed July 8, 1926 6 Sheets-Sheet 5 Dec. 23, 19 30. M. K. INGOLDBY LOCOMOTIVE Filed July 8, 1926 6 Sheets-Sheet 6 \\\\\\\\\\\N \\N nu Q Q v Patented Dec. 23, 1930 omen, 's'rA'rEs PATENTQOFFICE j gine of the locomotive and the MAURICE KER-R IN'GOLDBY, or WESTMINSTE LoNDoN, ENGLAND,- ASSIGN OB roe IN- LIMITED, or WESTMINSTER, EnGLAND; A

nniien 'eoiunus'rion nocoivrorrvns, BRITISH COMPANY 'Applica tion filed July 8,

T his invention relates to locomotives of the kind having an internal. combustion engine and a var able stroke type of hydraulic driving gear comprising one or more pump units driven by the internal combustion engine and of a locomotive designed in accordance with the invention. 1 Figure 2 showsdiagrammatically an an rangement of gearing and connecting rods for transmittingpower fromthe motor unit of the hydraulic gear to the locomotive driving wheels. i v

Figure '3 illustrates in vertical section a form of flexible coupling for use between the crank shaft of the internal combustion enpump unit of the hydraulic gear. 7 V 1 Figure 4 shows the pump and motor units a of the hydraulic gear the tilting boxes of which are interconnectcdso that both ofthem can be ad3u'sted.

Figure 5 represents diagrammatically the cooling system for cooling the internal co nbustion engine and the liquid in the hydraulic ear. f

Figure 6 is an end View o f-Figure" 5. 1 1 Figure Tillustrates in vertical section a fan and its casingifor circulating air over the water cooli.ngelenient ofthe cooling system illustrated in Figures 5 and Figure 8 a sectionalqilau view of Figure? l V I Figure 9 illustrates in vertical section gearing for driving tl e' fail, a cool n water circulating pump and a hydrauh=v liquid circulating pump. 1

Figure-1O is a plan of Figure 9; 1 Figure 11 illustratesdiagrammatically the pump and "motor units of thehydraulic gear provided with bypass valves for short circuiting the-suction and pressure sides of the Looo vro'rrvn i 1926. s'erial'No. 121,115. L

hydraulic matically.

Figure 12 is a detail View of a distributor valve which operates in conjunction with one of the by-pass valves in Figure 11 the distributor valve being shown'with its operative parts in the position they :would occupywhen gear either by hand or autot-he gear is running in the reverse direction to that represented by the disposition of the parts in Figure 11; Y

r F igurelS illustrates in vertical section a hydraulic rain for assisting in overcoming the resistance offered to the movements of thetilting box in the pump unit of the hy-v draulic gear. I V i I T Figure 14' illustrates in vertical section a spring operated device for balancing the overhanging weight of the tilting box of the pump unit, and V v F igure illustrates pipe connections between the hydraulic gear liquid circulating pump, liquid cooling element and the replenishing valves of the hydraulic gear whereby the back pressure experienced by said pump is used to effect the replenishment of the liquid in the hydraulic gear in the event of a deficiency of liquid arisingwhen the hydraulic gear is running at a compar- .7

atively high speed. 7

1 is the internal combustion engine. 2 isv the pump unit o f'the hydraulic gear and 3 the motor unit thereof. In the-locomotive illustrated the internal combustion'engine is of p the Diesel type and thehydraulic gear is of the Williams-Janney type.

' The drive between: the motorunit 3 of the hydraulic gear and the locomotivedriving wheels 4, at is effected by coupling'rods 5 (F ig-' 2 by gearing t5, 6 and,

and the other to the shaft of the pump unit of the hydraulic gear. The said members 8, 8 have on their peripheries a number of grooves 9, 9 in which a steel spring 10 made in segments is placed. The drive between the said members takes place across the springs which under normal running conditions are only slightly bent between their unsupported parts etween said n'ienibers. In the event, however, of the internal combustion engine producing a sudden shock as is liable to occur in starting the said springs by reason of their flexibility take up the shock which is expended in further bending the unsupported portions thereof between said members and is consequently not transmitted to the hydraulic gear.

The tilting boxes or swash plate. in both the pump unit and the motor unit of the hydraulic gear are made adjustable so that a large starting torque can be obtained when starting the locomotive by suitably adjusting both tilting boxes. The mechanism for effecting the adjustment of the tilting boxes interconnected and means are provided whereby adjustment to said tilting boxes can be made from either end of the locomotive. This is accomplished (see Figure 4) by providing a bevel wheel 11 on the shaft 12 of the pump unit 2 (which is the shaft usually provided for eE sting the adjustment of the tilting box Engaging with the bevel wheel 11 is a bevel wheel 13 secured to a shaft 14 rotatably mounted on the casing of the pump unit. A shaft 15 is similarly mounted on the motor unit 3 and engages by means of a worm 1.6 with a worm wheel 17. This worm wheel is formed with a cam surface 18 with which engages a pin 19 on an arm 20 which transmits movement to the tilting box 3 of the motor unit. The said shafts 14 and 15 are interconnected by means of a shaft 21. .The shafts 12 and 15 are extended as shown at 22 and 23 and suitably formed for the reception of gear wheels or other mechanism whereby they can be rotated. By a suitable system of extended shafts gearing 23*, etc., (see Fig. l)

' movement can be transmitted to either the shaft 22 or the shaft 23 from hand wheels 24*, 25* situated at either end of the locomotive and controlled by the driver thereof, this movement being transmitted to the tilting boxes in both the pump unit and motor unit by means of the interconnecting mechanism above described.

The internal combustion engine is cooled by water circulated by a pump 21 (see Figure 5) through a water cooling element consisting of radiators 25, and the hydraulic gear by circulation of the liquid used therein (which in this case is oil and hereinafter referred to as motive oil) through an oil cooling element consisting of two coolers '26, 26 by means of an oil circulating pump 27, which is preferably a variable stroke pump of the VVilliams-Janney type. This oil circulating pump also serves by means of oil pipe line 27* to circulate lubricating oil. to the locomotive bearings and other parts which require lubricating by circulating oil. Cooling air is forced over the radiators :25, 25 by means of a fan 28. 29 the cooling water outlet pipe from the water jac of the internal combustion engine and 3'.) is the inlet pipe thereto which pipe communicates with the exhaust side of the water circulating pump 24, the inlet side of said pump communicating with the radiators 25, by means of a pipe 31. The oil coolers 26, 26 have the lower ends of their water spaces connected by a pipe 32 whilst the upper ends of their water spaces are connected respectively to the internal combustion engine outlet pipe 29 and the radiators 525, the latter connection being effected by a pipe 33. For the purpose of replenishing the cooling water owing to loss by evaporation etc, an auxiliary tank 34!; is provided which is in connmniication with the radiators by pipes 35, 36. A pump 37 in the pipe enables water to be lifted from the auxiliary tank into the radiators when it is required to plenish the water therein. The pipe 36 serves as an overflow pipe from the radiators into the said auxiliary tank. The motive oil from the hydraulic gear passes through the pipes 38, 39 into the tank 10 from which it is pumped by the oil circulating pump 27 through the oil coolers 26 and pipe 41, into a tank 42 situated above the radiators. From this tank the cooled motive oil flows back to the hydraulic through the pipe 43 under the influence of gravity. The aforesaid tank 10 situated as low down as conveniently possible so to prevent air locks and also to enab e the an tive oil to settle so that it is not drawn by the oil circulating pump in a state of turbulence. By the above arrangement the motive oil of the hydraulic gear is initially heated by the hot cooling water from the engine and is subsequently cooled thereby and maintained at a predetermined temperature substantially that of the hot cooling water from the engine.

Control 27a is preferably of the screw and nut type, whereby the inclination of the tilting box of the pump 27 may be adju ted by the driver to give such output as is r quired for eflicient lubrication, cooling an circulation of the oil for the hydraulic gear.

The said motive oil circulating pump :2? is provided with means whereby its delivery can be varied so that the temperature of the motive oil in the hydraulic gear can be varied by controlling the rate of flow through the motive oil coolers thereby enabling the temperature of the hydraulic gear to be kept at the most suitable value depending upon the running conditions of the hy? raulic gear, such meansconsisting of a handcon- {trolled wheel'27a (see Figs-land adaptfed to vary the inclination of the tilting box inthe pump 27,,so' that its delivery maybe -altered. "The said. motive oil circulating pump also serves to provide-forced replenishmeut of motive oil to the suction or; negative pressure side of the hydraulic gear which becomes necessary when it isattempt- 10 ed to run the latter'at comparativelyl igh speeds,. thelnecessary pressure to effect-this being obtained by the resistance offered to the circulation of the motive oil through the oil coolers: or from the resistance offered by valves provided for the purpose.

This is accomplished bymea-ns of abranch pipe 53 (see Figs. .1 and situated between the pressure side of the:,1notive toil circulating pump 27 and the suction side of the active oil system of the hydraulic gear. "Under normalconditionsit is found that the resistance offered to the flow of the motive oil through the oil coolers 26 in sui'iicient to set up a pressure in the pipe high enough tocause motive oil tov enter the hydraulic gear in the event of a deficiency occurring therein. In some cases a valve 54 may be arran 'ed in the motive oil dischar e Dine b b n whereby the resistance 1n the pipe 53 can be gofurtliel increased and a larger volume of and the rotating blades 28 are driven from .the internal combustion engine 1 through suitable gearing and a slipping device; The gearing comprises toothed wheels 44:, 4:5 and 46 see Figures 1, 9 and 10) which transmit motion from the shaft connecting the internal combustion enginew'ith the pump unit of the hydraulic gear to a shaft 47 arranged above the pump unit 2 of the hydraulic gear which shaft transmits motion to the spindle 48 of the fan through crown Wheels 49 and 50. The slippingdevice is in the form of aplate clutch'51 arranged on the said shaft 47 so that sudden shocks which are experienced by the toothed wheels 44;,45 and it; are not transmitted totheshaft-i'i. The said shaft 4l7-inaddition to transmitting motion to the fan also serves to transmit motion to the, aforesaid cooling water and motive oil circulating pumps '24,, 27.- .For' this purpose the said shaft is provided with toothed wlieels t't' 47 (see Fig. 10) which engage with correspondingtoothed wheels onshafts 51, 52 arrangedionreither side of the said shafts? and parallel there- 01-,with. The shaft 51 serves to drive the motive oil circulating pump 27 and the shaft 52 the cooling Watercirculating pump 24. 'By-drivin g the cooling water and motive oil circulatingpu nps from, the shafts? these ti pumps aresafeguarded against sudden shock from the internal combustion engine by the :aforesaid clutch 51, y

' Means under the control of the driver of vthe locomotive are provided whereby the ,suction and pressure sides of the hydraulic gear can be short circuited: These means preferably comprise a-by-pass valve 53a see Fi ure 11 havin two )orts 54a 55,

z: t: l a r communicating respectively wvith the suction and pressure sides of the 'motor unit 3 ofthe hydrauliogear by pipes 56 and 57. Within. the casing of the bypass is a balanced sliding piston valve having two pis- 7 tons 58, 59 at opposite ends of a commonjpiston rodbO. The piston rod passes through 'one end of the casing of the Joy-pass and is adaptedto be connected by suitablelrods 63* and levers 64% to levers 65*, at each end i of the -locomotive under the control of the driver. By longitudinally displacing the saidpistonrod 60 the said pis tons canbeImoved 1nto a posltion where one of them covers the port 55 (as shownin the figure) in which position no passage of motive .oil from themotor unitthrough the .by-pass can take place and the motor unit operates in the ordinary manner. By displacingithe said piston rod in'the opposite direction however the port 55 can be uncovered by the piston59 thereby permitting motive oil from the pressure side of the motor unit to. be released into. the suction side via. the said by-pass which results inashort circuiting of the suction andpressure sides of the motor unit which consequently ceases totransmitjpower. For the purpose of retaining thefsaid pistons 58, 59 in their port opening or closingpositions a locking device- 61v is provided comprising a spring controlled plunger..62 adapted to enter one or I theother of grooves 63, 64 fo'rmed in the eX- tension ofthepiston rod 60, said grooves being so positionedthat one or the other of them is enteredby' the spring controlled -plunger when the pistons are moved into positionfor either opening or closing the said port 55. By means; of. this hand controlled by-pass valve creeping of, the motor unit can be. prevented when the, locomotive iswstanding at 'a station by short circuiting "the suction andpressure sides of the motor' unit'; also the locomotive can be moved by power other than its own when the by-pass valve'is moved into its short circuiting position. 7 I Means are'l also provided to safeguar againstexcessive pressure taking place in the hydraulic-gear. "These means comprise a by- 'pass-valve65 (see Figure 11) similar to that above de cribedbut adapted to be automatr; :i cally moved into the short cirouiting posi tion by the excess pressure in thehydraulic gear. 'The sa'idby-pass has two ports 66, 67 :which;communicate by pipes-68, 69' respeci'tivelywith ltliersuctionz andpressure: sidesof I the motor unit 3. 'lhe'pistons 7U, 71 of the by-pass are connected by a common piston rod 72, as in the previously described by-pass 53. At one end of the by-pass is arranged a casing 73 into which the piston extends. The portion of the piston extending into the casing '73 is made hollow for the reception of a flanged plug Tlwhich constitutes a closure for the The said plug 74 is bored out to conta'n a ram 75 adapted under certain circumstances to press against the piston 70 and displace the pistons in the bypass. ll. spring 76 is arrz'anged round the extended portion of the piston 70 between a flange 70 thereon and a suitable part of the by-pass asing and acts to retain the pistons 70, 71 in a position to close the port 67. The said plug 'Tt communicates by means of a pipe 77 and relief valves 78, 79 with the suction and pressure sides of the pump unit 2 of the hydraulic gear. In the event of an excess pressure arising in the pump unit beyond that determined by the setting of the relief valves 78, 79 motive oil passes one or other of these valves according to the direction of running of the hydraulic gear and enters the aforesaid memher or plug 74 by means of the pine 77 and a passage 80 in the plug '74; and displaces the ram75 in a direction which causes it to move the pistons 70, 71 into a position whereby the port 6'? is uncovered, the result being a shortcircuiting between the suction and pressure sides of the motor unit which thereby isrelieved of the excess pressure. On pressure ceasing to act upon the ram 75 the pistons are moved back into their normal. position to close the port 67 by the aforesaid spring 76 and the pump unit operates at its normal pressure. The said piston rod 72 extends through the opposite end of the by-pass casingto which the said casing 73 is situated and is provided with suitable means whereby it can be inter connected with the locomotive brake mechanism so that when the brakes are applied the said pistons 70, 71v are displaced into a position to establish com nnnicatirm between the ports 66, 67 and short circuit the suction and pressure sides of the motor unit. To enable the displacement of the pistons 70, 71 to take place when the locomotive brake mechanisin is operated the piston rod 72 is provided with a lin 'er 72 with which a projection 73* on a rod lis a da ted to engage. The rod 74* is connected to tie lin'zoinotive brake lever 75* so that when the latter is dis'ilaced to apply the brakes 75 the rod 74- is moved in the direction indicated by the arrow causing the 'ection 73* to bear against the linger 72* V displace the pistons 70, 71 to establish communication between the ports 66, 67 and short circuit the suction and pressure sides of the motor unit as aforesaid.

Means are also provided to safeguard against the undesirable effect which is likely to take place in the event of the locomotive over-running the hydraulic gear which might happen when for example the locomotive is proceeding downhill. These means comprise a distributor valve 80 (see Figures ll and 12) operating in conjunction with the above described automatically controlled by pass. The distributor valve 80 is a three ported valve, two of which ports are in communication with the suction and pressure sides of the pump unit 2 of the hydraulic gear by pipes 81, 82 respectively the third port being in communication with the aforesaid plug Tel appertainingto the by-pass 65 by a pipe 88. The said ports in the distributor valve are controlled by a sliding piston valve 84 which is adapted to be displaced by a lever 85 actuated by a pin or roller 85 carried thereby engaging in a cam surface 2 formed in a port carried by the tilting box 2 of the pump unit 2 0f the hydraulic gear is moved into position for forward or reve se running so that in eithe' case the port he distributor valve which communicates with the pressure side of the pump unit is closed and connnunication is established bee lc\ er n5 is displaced with the said tilbox. In the event of overrunning of 2e hydraulic gear taking place the momentum of the locomotive tends to drive the motor unit wnich then commences to act as a pump and pressure is generated in what are at the time of over-running the suction sides of the motor and pump units and this pressure is conducted to the aforesaid ram 75 n'ough the distributor valve and pipe 83. he ram then operates to move the pistons (ll '71 in the by-pass valve 65 into a position 'her short-circuiting between the suction 1nd pressure sides of the pump unit occurs thereby preventing the latter from driving the locomotive engine which would be the ca se otherwise. In Figure 11 for sake of clearness the pump or negative pressure and their delivery or motor units are shown diagrammatically and their suction and pressure ports are indicated by the segmental ports Sc, 8. Pa, Pb, respectively. In the actual gear the ports So and S?) would be in communication with each other and similarly the ports Pa, PI).

Means are provided to asFs-t in o wrcoming the re. nce offered against movement of the tiltu i boxes in the pump and motor units of the. h '-,-draulic giar. said means con'zpn'ising a.

' number of pistons 86 one of: which is shown l i-i piston rods 88 the lout er ends of which are connected to'the tilting boxes at or near their peripheries lay-means of ball and socket joints 89. The piston rods 88 in'the motor unit are surrounded byspiral springs 90,which react j between a flanged member 91 on the piston rods and an abutment on the exterior of the cylinders 87 to balance the resistance offered against movement ofthe'tilting box due to its overhanging"Weight. I-nthe' case of the pump unit :a"'similar but external device is used in which the overhanging weight ofthe tiltin box 'is balanced b s)1'=i11 "s 92 see Figure let) operating between a member 93 on a rod 94 which 1S attacl'ie'd to a crank 95 on the tilting box-trunnions and the closed end of a casing 96Ysurrounding said spring and pivotally attached by a bracket or plate 97 to a suitable fixed part of the hydraulic ear. 1 f i b lVhat I claim and desireto secure byLet-' ters Patent of theUn'ited States is 1. A locomotive consisting in the comb-ination of an internal combustion engine, an

hydraulic gearcoinprising apump unit'and a motor unit, driving wheels for said locomotive, means for driving the pump unit from the engine, means for" transmittingpower: from the motor unit'to the locomotive drivwheels coolingjxwater for said'engine,

and means for utilizing the coolingwater of the engineforfcooling the motive oil of the hydraulic gear. 1 V V I 2. Alocomotive consistingjin the combina "tion of an internal combustion engine, an

hydraulic gear comprising a pump unit and a motor unit, drlving wheels tor'said locomotive, means for 'drivlng the pump unit from the engine, meanstfor transmitting power from the motor unitto the locomotive driv ing wheels, an element for cooling the 'cool-' ing water'of theengine,and means forutilizing the cooling 'waterofjthe engine for'cool ing the 'motive oil of the hydraulic gear on 'its way to saidelement.

3; A; loconiotiveconsist-ing 1n the combination ofan internal combustion englne, an j hydraulic gear comprising pump unit and amotor' unit, driving wheels forthe locomotive, means'for driving'fthe pump unit from the engine, means for transmitting power from the motorfunit to the locomotive driving wheels, a watercooling el ementin communication with the Water jaeket'of the engine,

" an element for 'cooling'th'e motive oilof the hydraulicgear and means for'circulating the water through said elementsand water jacket.

4. Alo'comotive consisting in thecombina- ,tion of an internal combustion engine, "an

hydraulic gear comprlsin'ga pump unlt and,

a motor unit, driving-wheels for the locomotive, meansffordrivlng thepu'mp unlt from the engine, means toritranjsmitting power from the motor unitto the" locomotlve drivingwhee'lsj' awate'r cooling element in communication with the water jacket of" the engine, an element for cooling themotive oil of the hydraulic'gear, means for circulating the water through said element and water acket "and means tor circulating air over the water cooling elements.

5. .A locomotive consisting in the combinatlon of an lnternal combustion engine, an

hydraulic gear comprising a pump unit and a motor unit, driving wheel-s torsaid locomo -tive, means-for driving the pump unit from the engine, means for transmitting power fromthe motorunit to the locomotive driving wheels,a watercoolingelement in 0011']: munication with the water jacket of the engine, an element for coolil'ig the motive oil of the'hydraulic geammeans for circulating the vWater through said element and Water jacket, afan for circulating air over the water] coolingfelement' and means for driving said fan from the engine.

6. A locomotive consisting in the'combination of an internal combustion engine, an hydraulic gear comprising a pump unit and a motor'unit', driving wheels for said locomotive, meansfor driving the pumpunit from the engine, means for transmitting power from the, motor unit to the locomotive driving wheels, driving wheels for'said locomotive, a water cooling I element in communication with the water jacketot the engine and with an o'il cooling element forfc'ooling the motive oilo'f the hy'd-raullc gear, means for circulatlngthe Water through said element and waterf-jacket, a fan for circulating air over said water: cooling element and'mean's fordriving said fanithrough aslipping device located between the engine and the fan. 7 A'locomotive consisting in thecombination' of an internal combustion engine, an hydraulic gear comprising apump unit and a a clutch at the opposite end of saidshait for" connecting it with a second shaft drivenfrom theengine. V e

8 A locomotlve consisting in the combinationof an internal combustion engine, an hydrauli'cgear comprising a'fpumplu'nit and a' motor unit, driving wheels for'said locomotive, means for driving the pump unit from the engine, means for transmitting power from the motor unit to the'loco'motive driving wheels, an element for cooling the motive oil of the hydraulic gear, a water cooling element in communication with the water jacket of the engine and with said first element, means for circulating the water through said element and water acket, a fan for circulating air over said water cooling element, a drive shaft arranged longitudinally of the hydraulic gear, a second shaft driven by the engine, d iving means at one end of said drive shaft for transmitting motion to said fan, a clutch mounted on said drive shaft for connectin g the latter to said second shaft, a pump for circulating the cooling water through the water jacket of the engine and the said cool ing elements, and means for driving said pump from said drive shaft.

9. A locomotive consisting in the combination of an internal combustion engine, an hydraulic gear comprising a pump unit and a motor unit, driving wheels for said locomotive, means for driving the pump unit from the engine, means for transmitting power from the motor unit to the locomotive driving wheels, a pump for circulating the motive fiuid of the hydraulic gear, and means for varying the delivery of said fluid from the said circulating pump.

10. A locomotive consisting in the combination of an internal combustion engine, an hydraulic gear comprising a pump unit and a motor unit, driving wheels for said locomotive, means for driving the pump unit from the engine, means for transmitting power trom the motor unit to the locomotive driving wheels, an element for cooling the motive oil of the hydraulic gear, a water cooling element in communication with the water jacket of the engine and with said first element, means for circulating the water through said elements and water jacket, an auxiliary tank communicating with the water cooling element and means for supplying water from the auxiliar tank to the water cooling element.

11. A locomotive consisting in the combination of an internal combustion engine, an hydraulic gear comprising a pump unit and a motor unit, driving wheels for said locomotive, means for driving the pump unit from the engine, means for transmitting power from the motor unit to the locomotive driving wheels, a bypass having its ports in communication with the suction and pressure sides of the motor unit, a piston valve in said bypass and means under the control of the driver of the locomotive for moving said piston valve into a position for opening or closing said by-pass.

12. A locomotive consisting in the combination of an internal combustion engine, an hydraulic gear comprising a pump unit and a motor unit, driving wheels for said locomotive, means for driving the pump unit from the engine, means for transmitting power from the motor unit to the locomotive driving wheels, means for short-circuiting the pressure and suction sides of the hydraulic gear and means for automatically operating the short-circuiting means in the event of over-running of the hydraulic gear.

13. A locomotive consisting in the combination of an internal combustion engine, an hydraulic gear comprising a pump unit and a motor unit, driving wheels for said locomotive, means for driving the pump unit from the engine, means for transmitting power from the motor unit to the locomotive driving wheels, a by-pass having its ports in communication with the suction and pressure sides of the motor unit, a piston valve in said bypass, a cylinder at one end of said byp a ram in said cylinder for operating said piston valve, relief valves in communication with the suction and pressure sides of the motor unit and pipe connections between the cylinder and the relief valves.

14. A locomotive consisting in the combination of an internal combustion engine, an hydraulic gear comprising a pump unit and a motor unit, driving wheels for said loco motive, tilting boxes in the pump and motor units, means for driving the pump unit from the engine, means for transmitting power from the motor unit to the locomotive driv ing wheels, a by-pass having its ports in communication with the suction and pressure sides of the motor unit, a piston valve in said by-pass, a cylinder at one end of said bypass, a ram in said cylinder for operating the piston valve and means operating in conjunction with the movement of the pump unit tilting box for establishing communication between the cylinder and the suction side of the pump unit during both forward and reverse running of the hydraulic gear.

15. A locomotive consisting in the combination of an internal combustion engine, an hydraulic gear comprising a pump unit and a motor unit, driving wheels for said locomotive, tilting boxes in the pump and motor units, means for driving the pump unit from the en ine, means for transmitting power from the motor unit to the locomotive driving wheels, a by-pass having its ports in communication with the suction and pressure sides of the motor unit, a piston valve in the by-pass, a cylinder at one end of the bypass, a ram in the cylinder for operating the piston valve, a distributor valve in communication with the cylinder and the suction sides of the pump unit operated by the movement of the pump unit tilting box to close the pres sure side of the pump unit and establish communication between the suction side thereof and the cylinder according to the direction of running of the hydraulic gear.

16. A locomotive consisting in the combination of an internal combustion engine, a hydraulic driving gear comprising a pump unit and a motor unit, driving Wheels for said locomotive, means for driving'the pump unit from the engine, means for transmitting power from the motor unit to the locomotive driving Wheels, cooling Water for cooling the said engine, and means for utilizing the cool ing Water of the engine to heat initially and subsequently cool the-motive oil of the hydraulic gear;

17. A locomotive consisting in the combination of an internal combustion engine, a hydraulic driving gear comprising a pump unit and a motor unit, driving Wheels for said locomotive means for driving the pump unit from the engine, means for transmitting power from the motor unit to the locomotive driving Wheels, Water for removlng the excess heat developed by said engine, and means for utilizing the resultantly heated water of the engine to heat initially the motive oil of the hydraulic gear.

MAURICE KERR INGOLDBY. 

